Elevator safety switch control



ELEVATOR SAFETY SWITCH CONTROL Filed Sept. 16. 1933 MC. [100M 315:1 w il' l M I 4 .7' 7 /7/a' M 15/2 4 i i Lif/THARDEMAN warms; I i I Patented Sept. 25, 1934 1,974,848 ELEVATOR SAFETY SWITCH CONTROL Lee Frank Hardeman,

of one-third to third to Memphis, Tenn., assignor Selwyn D. Tucker and one- Leslie A. Thornton Application September 16, 1933, Serial No. 689,773

. 3 Claims.

This invention relate'sto elevator safety switch controlling devices and aims generally to improve the same." i

Particular objects of the invention are to providean improved central safety switch operating mechanism controlled by. opening and closing of the landing doors, and to provide improved means for transmitting the motion of the doors to the switch operating tape or the like.

In the accompanying drawing showing a preferred embodiment illustrative of my invention:

Fig. 1 is a diagran'unaticv view of my device incorporated in an elevator system including a pluralityof landing doors;

.Fig. 2 is a detailed, elevation of the motion transmitting means of my device showing in solidlines its position when the doors are closed, and in dotted lines its position when the doors are open; and

Fig. 3 is a vertical detail View, partly in section,

taken at right angles to Fig. 2. The elevator system indicated diagrammatically in Fig. 1 comprises the usual elevator shaftway provided with a plurality of landing door installations l0-11, which. may be of any usualtype. Simply as representative of any doors I have indicated doors of the double slidingtype operated by a door operating means including the arm 12, swingableabout a pivot. 13, the bell crank 14 pivoted thereto at 15 and swingable about the pivot l6 on the nearer door section, and the link 1'7 pivoted to the bell crank at 18, and to the more remote door section 11 at 19, the only portion of the door operating linkages concerned in the illustrative embodiment of my invention being the arms 12, swingable about the pivots 13.

Other principal parts of the elevator system which will be found in the usual installation include the elevator car 20, indicated in dotted lines, and the elevator driving mechanism shown diagrammatically as comprising a driving drum 21 and cable 22, operated by a motor 23.

In accordance with the illustrative embodiment of Fig. 1, instead of utilizing an individual make and break switch for each door, for cutting oii the current supply to the motor 23 when a door is open, my invention makes use of a central 'make and break safety switch 25, the circuit 26 of which is arranged to so control the current .supply to the motor 23. If this arrangement is "efiected by including the safety switch directly in series with the power lines to the motor 23, then closing of the switch 25 will render the elevator driving means operable, and opening thereof will render the same inoperable. If the switch 25 be included in a pilot circuit controlling a solenoid operated switch, for example, the type of solenoid switch employed will determine whether the elevator driving circuit will be closed or opened when the circuit of the switch 25 is made.

In whatever way this is arranged, however, by my invention, means, shown as a weight mechanism, herein made up of the short tape 30, the sheave 31 and the weight 32, is associated with the switch 25 to urge it toward safety position, i. e. toward that position which will effect cutting off of the current supply to the-motor 23 and further means, herein the control tape 35 and weight 36 rendering the same additionally heavy, is arranged to offset the tendency of the weight mechanism -32 to open the circuit, thus to maintain the circuit closed so long as the force of the weighted tape -36 is not rendered inactive by the operation of means associating the tape 35 with the several door installations 10-19.

In the preferred embodiment these last named means, as best shown in Figs. 2 and 3, each consists of a lost motion device of preferred construction, interconnecting the tape 35 with the swingable lever 12 of the door opening mechanism, so that the swinging of any one of said levers 12 will effect lifting of the tape 35 and weight 36, allow ing the weight mechanism 30-32 to operate the switch 25 to safety position. It will be appreciated that as the tape 35 is quite flexible, the means3032 should be sui'liciently powerful to insure lifting of the weight of all of that part of the tape 35 above the most remote, hereinthe lowermost, door-and-tape associating lost motion means.

In the preferred construction shown in Figs. 2 and 3, the lost motion device comprising a stop, herein a pair of discs 40 having flattened lower edges 41, and clamped to the tape 35 by means such as the bolts 42, and a box 43 therebelow through which the tape 35 is freely slidable and which is carried on the swingable lever 12 of the door opening mechanism, in spaced relation to the pivot 13 thereof, to be raised against the stop 40-42 as said lever is operated to door-open position, thus to raise the tape 35, moving the other stop or stops 40 away from their associated boxes 43, and allowing the weig t mechanism 30- 32 to move the switch 25 to safety position. Thus by the accurate fixing of the stops 4042 on the tape 35 at each landing door in the height of travel of the elevator 20, the single central switch 25 will be moved to safety position in the event that any door in the shaft be opened.

An important feature of the invention is the thus formed, and securing a peculiar arrangement of the boxes 43 which are so mounted on the swingable arms 12 as to be freely turnable thereon as they are raised thereby, and thereby permitted to remain level at all times, preventing any twisting strain on the stops 40-42 which might eventually work the same along the tape to an inoperative position, and preventing any short bending of the tape 35 which might eventually cause breakage thereof. In the form shown (see Fig. 3) the box 43 is drilled at 44 and counterbored at 45, to accommodate the bolt 46, extended through the bore 44 with its head positioned within the counterbore 45 of the box 43, which bolt 46 is rigidly secured in an aperture 47 in the arm 12 by means of a pair of nuts 48 threaded thereto, and brought to a tight bearing, one on either side of the arm 12. This construction leaves the box 43 free to rotate on the shank of the bolt 46 as a pivot.

The slidable association of the box 43 with the tape 35, in the form shown, is effected by slotting the face of the counterbored end of the box 43, as indicated at 49, inserting the tape 35 in the slot retaining plate 50 thereover in any suitable way, as by the machine screws 51.

From the foregoing description of the embodiment shown in the drawing it will be perceived 1 that the control arrangement of my invention is lever in spaced relation particularly flexible and sure in operation, that it is cheap and easily installed and maintained, and that my new construction of the means interconnecting the door installations and tape is particularly desirable inasmuch as it minimizes breakage of the parts and the likelihood of misplacement thereof.

My invention may obviously be embodied in other forms than that herein disclosed to illustrate the same, which fact is to be borne in mind in interpreting my specification and claims, and having described such preferred embodiment, I claim:

1. In an elevator system, a shaftway having a plurality of landing door installations, a control tape extending past said several door installations, and lost motion means interconnecting said tape with each of said door installations, said door installations each including a door opening lever swingable about a pivot, andeach of said lost motion means comprising a stop on said tape and a box freely slidable on said tape adjacent said stop, said box being freely pivoted to said to the pivot of the latter that it may turn thereon as it is swung therewith, to thus exert its thrust against said stop linearly of said tape and avoid straining thereof.

2. In an elevator system, a shaftway having a plurality of landing door installations, a control switch above the uppermost of said door installations, a weight mechanism adjacent said control switch tending to open the same, a weighted tape depending past said several door installations and connected to offset the action of said weight mechanism and hold said control switch in closed position, and lost motion means associating said tape with each of said door installations in such manner that opening of any one of said doors effects lifting of said weighted tape, thereby allowing said weight mechanism to open said control switch, said landing door installations each including a door opening lever upwardly swingable about a pivot, and each of said lost motion means comprising a stop on said tape and a box below said stop through which said tape is freely slidable, said box being freely pivoted to said lever in spaced relation to the pivot of the latter that it may turn thereon as it is raised therewith, to thus exert its thrust against said stop linearly of said tape and avoid straining thereof.

3. In an elevator system, an elevator shaftway having a plurality of landing door installations, an elevator in said shaftway, means including an operating circuit for moving the elevator car, a safety switch for making and breaking said operating circuit to render said means operable and non-operable, a tape extending from said switch and adjacent said plurality of landing doors and adapted by its longitudinal movement to control said switch, means tending to open said switch, means including said tape and normally restraining said last named means, lost motion means interconnecting said tape with each of said door installations in such manner that opening of any of said doors renders the means including said tape inoperative to restrain said switch opening means, each of said lost motion means comprising a stop on said tape and a box freely slidable on said tape adjacent said stop, said box being freely pivoted to said lever in spaced relation'to the pivot of the latter that it may turn thereon as it is swung therewith, to thus exert its thrust against said stop linearly of said tape and avoid straining thereof.

LEE FRANK HARDEMAN. 

